Insulating composite plate

ABSTRACT

The present application provides an insulating composite plate comprising: an upper plate layer, a lower plate layer, and a middle plate layer, wherein the upper plate layer and the lower plate layer are made of a thermoplastic material; the middle plate layer is located between the upper plate layer and the lower plate layer, the middle plate layer being a metal mesh; the upper surface of the middle plate layer and the lower surface of the upper plate layer are bonded together, and the lower surface of the middle plate layer and the upper surface of the lower plate layer are bonded together. An insulating composite plate provided by this application has good insulation properties and can shield electromagnetic interference.

TECHNICAL FIELD

The present application relates to an insulating composite plate, andmore particularly to an insulating composite plate with anelectromagnetic shielding function for applications requiringsimultaneous electromagnetic shielding and insulation.

BACKGROUND ART

Insulating plates are used to insulate various electronic devices orcomponents to avoid failures caused by electronic short circuits andbreakdowns between electronic devices or units, or electronic componentsin electronic devices or units, and to reduce the risks of fire ofelectronic devices or components, thereby ensuring the normal operationof various types of electronic components. For different uses ofinsulating plates, insulating films are required to have differentoperating characteristics.

Therefore, it is desirable to provide an insulating plate havingexcellent properties.

SUMMARY OF THE INVENTION

According to a first aspect of the present application, an insulatingcomposite plate is provided, comprising:

an upper plate layer and a lower plate layer, the upper plate layer andthe lower plate layer being made of a thermoplastic material; and

a middle plate layer located between the upper plate layer and the lowerplate layer, the middle plate layer being a metal mesh;

the upper surface of the middle plate layer and the lower surface of theupper plate layer are bonded together, and the lower surface of themiddle plate layer and the upper surface of the lower plate layer arebonded together.

In the plate as described above, the upper plate layer and the lowerplate layer are bonded together at the position of the openings of themetal mesh.

The plate as described above is characterized in that:

the insulating composite plate is configured for molding into a batterypack cover shape;

the battery pack cover is configured for mounting on a battery packhousing.

The plate as described above is characterized in that:

the insulating composite plate is formed to have four walls extendingfrom its peripheral edges to form a battery pack cover.

The plate as described above is characterized in that:

the thermoplastic material is a thermoplastic resin.

The plate as described above is characterized in that:

the insulating composite plate is made by cast heat press molding orco-extrusion process;

in the manufacturing process, the thermoplastic material on the upperplate layer and/or the lower plate layer penetrates the openings of themetal mesh in a molten state, and comes into contact with the lowerplate layer or the upper plate layer on the other side of the metalmesh; after the thermoplastic material in a molten state is solidified,the upper plate layer is integrated with the lower plate layer so thatthe metal mesh is locked between the upper plate layer and the lowerplate layer.

In the plate as described above, the plate upper layer and the platelower layer are bonded together without using an additional medium.

In the plate as described above, the thermoplastic resin forming theupper plate layer and the lower plate layer penetrates the openings ofthe metal mesh in a molten state, so that the upper plate layer and thelower plate layer are bonded together.

In the plate as described above, the upper plate layer and the lowerplate layer are made of the same material.

In the plate as described above, the plate upper layer and the platelower layer are made of different kinds of materials.

In the plate as described above, the thermoplastic material may beselected from PP, PC or PET.

In the plate as described above, the thermoplastic material is PP.

In the plate as described above, neither the upper plate layer nor thelower plate layer contains a flame retardant.

In the plate as described above, the upper plate layer and the lowerplate layer contain a flame retardant.

In the plate as described above, the flame retardant is ahalogen-containing flame retardant or a halogen-free flame retardant,the halogen-containing flame retardant being a bromine-containing flameretardant or a chlorine-containing flame retardant, the halogen-freeflame retardant being a phosphorus-containing flame retardant or anitrogen-containing or silicon-containing or sulfur-containing orinorganic flame retardant.

With the plate as described above, in the case of using a flameretardant in the upper plate layer and the lower plate layer, the flameretardancy rating of the plate is V-2 or VTM-2 or higher, or V-0 orVTM-0, and meets the RoHS standard.

In the plate as described above, the metal mesh is made of copper, oranother metal, or an alloy.

In the plate as described above, the metal mesh is made of copper or analloy thereof.

In the plate as described above, the metal mesh has a specification of20 openings to 400 openings, or 50 openings to 100 openings.

In the plate as described above, the thickness of the upper plate layeris 0.05 mm to 4.0 mm, or 0.43 mm to 2 mm; the thickness of the middleplate layer is 0.05 mm to 0.4 mm; the thickness of the lower plate layeris 0.05 mm to 4.0 mm, or 0.43 mm to 2 mm.

In the plate as described above, the plate has a thickness of 0.15 mm to5.0 mm, or 0.75 mm to 4 mm, or 1.5 mm to 3 mm, the plate has a CTI of250 volts or higher, or 600 volts or higher, and the plate has an RTI of90° C. or higher.

The plate as described above is produced by cast heat press molding orco-extrusion process.

According to a second aspect of the present application, a method forproducing an insulating composite plate is provided, the methodcomprising:

(a) extruding particles of a first thermoplastic material on an extruderto melt it to form a first thermoplastic material in a molten state;

(b) the first thermoplastic material in a molten state flows out of theextruder and enters a head die through a connecting pipe and is formedinto a first plate thermoplastic material in the head die;

(c) providing a metal mesh;

(d) simultaneously conveying the metal mesh and the first platethermoplastic material to a cooling molding roll so that the first platethermoplastic material is press-fitted on one surface of the metal meshto form a press-fitted sheet composed of the first plate thermoplasticmaterial and the metal mesh;

(f) extruding particles of a second thermoplastic material on theextruder to melt it to form a second thermoplastic material in a moltenstate;

(g) the second thermoplastic material in a molten state flows out of theextruder and enters the head die through the connecting pipe and isformed into a second plate thermoplastic material in the head die;

(h) simultaneously conveying the press-fitted sheet and the second platethermoplastic material to the cooling molding roll so that the secondplate thermoplastic material is press-fitted on the other surface of themetal mesh, forming the insulating composite plate comprising a middleplate layer composed of the metal mesh and an upper plate layer and alower plate layer respectively composed of the first plate thermoplasticmaterial and the second plate thermoplastic material.

In the method for producing an insulating composite plate as describedabove, the first thermoplastic material and the second thermoplasticmaterial are each selected from PP, PC or PET.

In the method for producing an insulating composite plate as describedabove, the first thermoplastic material and the second thermoplasticmaterial are the same or different.

In the method for producing an insulating composite plate as describedabove, the metal mesh is provided by unwinding from a metal mesh roll toconvey the metal mesh to the cooling molding roll.

In the method for producing an insulating composite plate as describedabove, the press-fitted sheet formed in step (d) is wound into apress-fitted sheet roll, and the press-fitted sheet is unwound from thepress-fitted sheet roll to convey the press-fitted sheet to the coolingmolding roll.

In the method for producing an insulating composite plate as describedabove, the thicknesses of the upper plate layer and the lower platelayer are determined by controlling the speed at which the first platethermoplastic material and the second plate thermoplastic material exitthe head die and the rotational speed of the cooling molding roll.

The method for producing an insulating composite plate as describedabove comprises step (i) of heating the press-fitted sheet before step(h).

In the method for producing an insulating composite plate as describedabove, the thermoplastic material on the upper plate layer and/or thelower plate layer penetrates the openings of the metal mesh in a moltenstate, and comes into contact with the lower plate layer or the upperplate layer on the other side of the metal mesh; after the thermoplasticmaterial in the molten state is solidified, the upper plate layer isintegrated with the lower plate layer so that the metal mesh is lockedbetween the upper plate layer and the lower plate layer.

According to a third aspect of the present application, a method forproducing an insulating composite plate is provided, the methodcomprising:

(a) extruding particles of a first thermoplastic material on a firstextruder to melt it to form a first thermoplastic material in a moltenstate;

(b) the first thermoplastic material in a molten state flows out of thefirst extruder and enters a first head die through a first connectingpipe and is formed into a first plate thermoplastic material in thefirst head die;

(c) extruding particles of a second thermoplastic material on a secondextruder to melt it to form a second thermoplastic material in a moltenstate;

(d) the second thermoplastic material in a molten state flows out of thesecond extruder and enters a second head die through a second connectingpipe and is formed into a second plate thermoplastic material in thesecond head die;

(e) providing a metal mesh;

(f) simultaneously conveying the metal mesh, the first platethermoplastic material, and the second plate thermoplastic material to acooling molding roll so that the first plate thermoplastic material andthe second plate thermoplastic material are respectively press-fitted onthe two opposing surfaces of the metal mesh, forming the insulatingcomposite plate comprising a middle plate layer composed of the metalmesh and an upper plate layer and a lower plate layer respectivelycomposed of the first plate thermoplastic material and the second platethermoplastic material.

In the method for producing an insulating composite plate as describedabove, the first thermoplastic material and the second thermoplasticmaterial in a molten state penetrate the openings of the metal mesh tocome into contact with each other; after the first thermoplasticmaterial and the second thermoplastic material in a molten state aresolidified, they are integrated so that the metal mesh is locked betweenthe upper plate layer and the lower plate layer.

In the method for producing an insulating composite plate as describedabove, the first thermoplastic material and the second thermoplasticmaterial are each selected from PP, PC or PET.

In the method for producing an insulating composite plate as describedabove, the first thermoplastic material and the second thermoplasticmaterial are the same or different.

In the method for producing an insulating composite plate as describedabove, the metal mesh is provided by unwinding from a metal mesh roll toconvey the metal mesh to the cooling molding roll.

In the method for producing an insulating composite plate as describedabove, the thicknesses of the upper plate layer and the lower platelayer are determined by controlling the speed at which the first platethermoplastic material and the second plate thermoplastic material exitthe head die and the rotational speed of the cooling molding roll.

A composite plate provided by the present application has excellentinsulation performance and electromagnetic shielding function, and isapplicable to isolating various electronic components.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present application canbe better understood by reading the following detailed description withreference to the accompanying drawings. In the drawings, the samereference numerals indicate the same parts, wherein:

FIG. 1 is a schematic cross-sectional view of an insulating compositeplate according to an embodiment of the present application;

FIG. 2 is another schematic cross-sectional view of the insulatingcomposite plate shown in FIG. 1 for schematically illustrating a statewhere the upper plate layer 101 and the lower plate layer 103 penetratethe openings 105 of the metal mesh 102 to be bonded together;

FIGS. 3A and 3B illustrate a cast heat press molding process of aninsulating composite plate according to an embodiment of the presentapplication;

FIG. 4 shows a co-extrusion process of producing an insulating compositeplate according to an embodiment of the present application;

FIG. 5 is a top view of a metal mesh in an insulating composite plate ofthe present application;

FIG. 6 is a schematic view of a battery pack cover made of an insulatingcomposite plate of the present application;

FIG. 7 is a schematic view of the battery pack cover in FIG. 6 on thebattery pack housing.

SPECIFIC EMBODIMENTS

Various embodiments of the present application will be described belowwith reference to the accompanying drawings, which form a part of thisSpecification. It should be understood that, although terms indicatingdirections, such as “front”, “back”, “upper”, “lower”, “left”, and“right”, are used in this application to describe various exemplarystructural components and elements, these terms are used herein forconvenience of illustration only and are determined on the basis of theexemplary orientations shown in the figures. Since the embodimentsdisclosed in the present application can be set in different directions,these terms indicating directions are merely illustrative and should notbe construed as limiting. In the following drawings, the same referencenumerals are used for the same components, and similar referencenumerals are used for similar components to avoid redundant description.

FIG. 1 shows a schematic cross-sectional view of an insulating compositeplate 100 according to an embodiment of the present application. Asshown in FIG. 1, the plate 100 comprises an upper plate layer 101, amiddle plate layer 102, and a lower plate layer 103 bonded together. Theupper plate layer 101 and the lower plate layer 103 are made of athermoplastic material so that the plate 100 has a good insulationeffect. The thermoplastic material may be a thermoplastic resin. Thethermoplastic materials used to make the upper plate layer 101 and thelower plate layer 103 may be the same or different. The thermoplasticmaterial used to make the upper plate layer 101 and the lower platelayer 103 may be PP, PC or PET. In one embodiment, PP is used as thematerial of the upper plate layer 101 and the lower plate layer 103. Thereasons are as follows: (1) PP is a non-toxic, odorless, tasteless milkywhite crystalline polymer with a density of 0.90 g/cm³ to 0.91 g/cm³,which is one of the lightest varieties in all plastics. Therefore, whenPP is selected as the material of the upper plate layer 101 and thelower plate layer 103, a plate 100 with a lighter overall weight can beobtained to meet the requirements for plate weight in an actualapplication (such as a battery pack cover plate for an electricvehicle); (2) In addition, PP as a hydrophobic polymer material withexcellent electrical insulation properties. Use of PP as the material ofthe upper plate layer 101 and that of the lower plate layer 103 canallow the plate 100 to deliver better insulation performance; (3) Themolding performance of PP is good, making it easy to obtain the plate100 through a molding process; (4) PP has a melting point of 164° C. to170° C., and has good heat resistance. A product can be used under 125°C. for a long period of time. It is not deformed under 150° C. withoutexternal force, so that the plate 100 delivers the high-temperatureresistance required in practical applications (for example, when it isused as a battery pack cover); (5) PP has very good chemical stability.Except being corroded by concentrated sulfuric acid, concentrated nitricacid, or strong oxidants, it is relatively stable to other chemicalreagents, so that it can meet the solvent resistance performancerequirement on the plate 100 in a practical application (such as thebattery pack cover of an electric vehicle).

Optionally, a flame retardant or no flame retardant may be added to thethermoplastic material of the upper plate layer 101 and/or the lowerplate layer 103. When a flame retardant is added to the thermoplasticmaterial of the upper plate layer 101 and/or the lower plate layer 103,the flame retardant is a halogen-containing flame retardant or ahalogen-free flame retardant, the halogen-containing flame retardantbeing a bromine-containing flame retardant or a chlorine-containingflame retardant, the halogen-free flame retardant being aphosphorus-containing flame retardant or a nitrogen-containing orsilicon-containing or sulfur-containing or inorganic flame retardant.Whatever kind of flame retardant is added to the thermoplastic materialof the upper plate layer 101 and/or the lower plate layer 103, the RoHSstandard is met. In addition, the plate retardancy rating can reach V-2or VTM-2 or higher, and can even reach V-0 or VTM-0.

The middle plate layer 102 is located between the upper plate layer 101and the lower plate layer 103. The middle plate layer 102 is a metalmesh, so that the insulating composite plate 100 of the presentapplication has an electromagnetic shielding function. The metal mesh ofthe middle plate layer 102 is embedded in the surfaces of the upperplate layer 101 and the lower plate layer 103 to form a firm connectionbetween the upper plate layer 101, the middle plate layer 102, and thelower plate layer 103. FIG. 5 shows a schematic structural diagram forthe metal mesh. The metal mesh may be copper or another metal, or analloy of copper or another metal. In one embodiment, the metal mesh iscopper or an alloy thereof. In another embodiment, the metal mesh iselemental copper. Due to the good ductility of copper, when elementalcopper is used to manufacture the metal mesh of the middle plate layer102, it is advantageous for the subsequent thermoforming to form themetal mesh. The number of openings of the metal mesh is related to theelectromagnetic shielding effect and the forming and processing of aproduct. For the electromagnetic shielding effect of the metal mesh, thelarger the number of openings of the metal mesh is, the better it is;for the forming and processing of a metal mesh product, the smaller thenumber of openings of the metal mesh is, the better it is. Consideringthe two factors comprehensively, the number of openings of the metalmesh is usually 20 to 400, or 50 to 300, or 50 to 200, or 50 to 100, or80. The diameter of a metal wire may be 0.01 mm to 0.2 mm, the spacingbetween adjacent metal wires may be 0.05 mm to 0.3 mm, and the thicknessof the metal mesh may be 0.05 mm to 0.4 mm. The number of metal meshopenings disclosed in the present application makes it possible toachieve a good electromagnetic shielding effect while facilitating theforming and processing of a product.

In the process of bonding the upper plate layer 101, the middle platelayer 102, and the lower plate layer 103, at least one of the upperplate layer 101 and the lower plate layer 103 is in a molten state.Thus, the thermoplastic materials of the upper plate layer 101 and/orthe lower plate layer 103 in a molten state penetrate the openings ofthe metal mesh to come into contact with the lower plate layer 103 orthe upper plate layer 101 on the other side of the metal mesh. After themolten thermoplastic material cools and solidifies, it is bonded to thelower plate layer and/or the upper plate layer 101 to form an insulatingcomposite plate of the present application.

FIG. 2 is another schematic cross-sectional view of the plate 100, forschematically showing a state where the upper plate layer 101 and thelower plate layer 103 are bonded together through the openings of themetal mesh. As shown in FIG. 2, at the position of the mesh openings 105of the metal mesh of the middle plate layer 102, the thermoplasticmaterials of the upper plate layer 101 and/or the lower plate layer 103penetrate the openings 105 of the metal mesh and are bonded together. Asshown in FIG. 2, the portions of the upper plate layer 101 and the lowerplate layer 103 that penetrate the mesh openings 105 of the metal meshare bonded as if formed integrally. By this type of bonding, the upperplate layer 101 and the lower plate layer 103 can be bonded togetherwithout using any other medium, for example, glue. In addition, themethod for bonding the upper plate layer 101 and the lower plate layer103 of the insulating composite plate 100 of the present application issuch that the upper plate layer 101 and the lower plate layer 103 aretightly bonded together for a long time, as if formed integrally.Therefore, there is no separation between the upper plate layer 101, themiddle plate layer 102, and the lower plate layer 103. In addition,there is no gap between the upper plate layer 101, the middle platelayer 102, and the lower plate layer 103. Thus, moisture cannot enterbetween the upper plate layer 101, the middle plate layer 102, and thelower plate layer 103 to corrode the metal mesh of the middle platelayer 102.

The thickness of the upper plate layer 101 of the insulating compositeplate 100 of the present application is 0.05 mm to 4.0 mm, the thicknessof the middle plate layer 102 is 0.05 mm to 0.4 mm, or 0.43 mm to 2 mm,the thickness of the lower plate layer 103 is 0.05 mm to 4.0 mm, or 0.43mm to 2 mm, and the total thickness of the plate is 0.15 mm to 5.0 mm,or 0.75 mm to 4 mm, or 1.5 mm to 3 mm. The thickness of an insulatingcomposite plate of the present application can meet the customerrequirements for the mechanical properties of plates. The ComparativeTracking Index (CTI) of the insulating composite plate 100 of thepresent application may be 250 volts or higher, and may even reach 600volts or higher, particularly when the thermoplastic material used formanufacturing the insulating composite plate 100 of the presentapplication is PP, PC or PET. When, for example, PP is selected as athermoplastic material for manufacturing the insulating composite plate100 of the present application, the insulating composite plate 100 ofthe present application can reach a higher CTI. The Relative ThermalIndex (RTI) of the insulating composite plate 100 of the presentapplication can reach 90° C. or higher.

The insulating composite plate 100 of the present application has thefollowing benefits:

The insulating composite plate 100 of the present application has a goodinsulating effect because of the upper plate layer 101 and the lowerplate layer 103 made of a thermoplastic material. In addition, since themiddle plate layer 102 of the insulating composite plate 100 of thepresent application is a metal mesh, the insulating composite plate 100of the present application also has the function of electromagneticshielding.

The inventors have noticed that in applications requiring insulation ofcomponents, insulating plates are generally used for the purpose ofinsulation; in applications requiring electromagnetic shielding, metalplates are generally used for electromagnetic shielding; in applicationsrequiring both insulation and electromagnetic shielding, a combinationof insulating plates and metal plates is needed. In the insulatingcomposite plate 100 of the present application, an insulating materialand a metal mesh are combined so as to meet the application requirementsfor both insulation and battery shielding.

In addition, the inventors have observed that, due to the heavy weightof a metal plate, electromagnetic shielding by a metal plate causes anincrease in the weight of an apparatus or a device using the metalplate. Consequently, various problems occur, such as an increase inenergy consumption of the apparatus or the device. The insulatingcomposite plate 100 of the present application has a relatively smallweight because the plate 100 of the present application has the upperplate layer 101 and the lower plate layer 103 made of a thermoplasticmaterial. Therefore, compared with the use of a metal plate forelectromagnetic shielding, electromagnetic shielding using theinsulating plate 100 of the present application reduces the weight of anapparatus or device, and thus avoids the problems caused when the deadweight of the metal plate is too large, for example, reducing theapparatus or device weight, which in turn reduces energy consumption.

In addition, the upper plate layer 101 and the lower plate layer 103 ofthe insulating composite plate 100 of the present application are bondedtogether through the openings of the metal mesh of the middle platelayer 102 in a molten state during the forming process, as if formedintegrally. Thus, the upper plate layer 101 and the lower plate layer103 can be firmly and tightly bonded together for a long time withoutseparation. In addition, there is no gap between the upper plate layer101, the middle plate layer 102, and the lower plate layer 103. Thus,moisture cannot enter between the upper plate layer 101, the middleplate layer 102, and the lower plate layer 103 to corrode the metal meshof the middle plate layer 102. Moreover, the metal mesh of the middleplate layer 102 is embedded or at least partially embedded in thesurfaces of the upper plate layer 101 and the lower plate layer 103,further strengthening the bonding strength between the layers of theplate 100.

The insulating composite plate 100 of the present application issuitable for use in various applications requiring electromagneticshielding and insulation. In particular, the insulating composite plate100 of the present application is particularly suitable for use as abattery pack cover for an electric vehicle due to the benefits describedabove. At present, global energy and the environment are facing enormouschallenges. As a major petroleum consumer and carbon dioxide emitter,the automobile industry needs to undergo revolutionary changes. In orderto reduce carbon dioxide emissions, a consensus has been reached on thedevelopment of new energy vehicles on a global scale. From a long-termpoint of view, pure electric drive including pure electric and fuel celltechnologies will be the main technical direction of new energyvehicles. In the short term, oil/electric hybrid power and plug-inoil/electric hybrid power will be an important transition route. Atpresent, the research and development hot spots of electric vehicles aremainly the improvement of operating range. The direction of improvementis, on the one hand, from the improvement of battery technology, and onthe other hand, from the reduction in the vehicle body weight under thepremise of ensuring the safety of vehicles. Since the battery in anelectric vehicle emits electromagnetic waves during operation,electromagnetic interference with other electronic components of thevehicle is easily generated and the human body is adversely affected.The current solution is to add a metal cover plate above the battery.However, a metal cover plate is relatively heavy. Therefore, adding ametal cover plate above a vehicle battery increases the weight of thevehicle body, and thus leads to higher vehicle energy consumption, whichis not conducive to improving the operating range of the electricvehicle. A battery pack cover for an electric vehicle produced by usingthe insulating plate 100 of the present application not only enables abattery pack cover to have a good insulating effect but also has thefunction of electromagnetic shielding. In addition, since a battery packcover made of the insulating composite plate 100 of the presentapplication has a significantly smaller dead weight compared with ametal plate in the prior art, the vehicle body weight is reduced andthus the vehicle energy consumption is reduced. Therefore, thedevelopment expectation of increasing the operating range of electricvehicles is met. Moreover, since the layers of the insulating compositeplate 100 of the present application can be firmly and tightly bondedtogether for a long time without separation, no gap exists between thelayers of the plate, so that moisture cannot enter between the layers ofthe plate to corrode the metal mesh of the middle plate layer 1. Thus,the insulating composite plate 100 of the present application canmaintain an excellent electromagnetic shielding effect for a long time.

FIG. 6 is a schematic view of a battery pack cover 600 made of theinsulating composite plate 100 according to the present application. Thebattery pack cover 600 is formed in a shape of four walls extending fromthe peripheral edges for covering the battery pack housing, so that thefour walls of the battery pack cover 600 extending from the peripheraledges surround the four walls of the battery pack housing. FIG. 7 showsa schematic view of the battery pack cover 600 in FIG. 6 covered on thebattery pack housing.

FIGS. 3A and 3B are schematic views of a cast heat press molding processof the plate 100 according to an embodiment of the present application.The cast heat press molding process comprises an extrusion apparatus 301and a molding apparatus 302. The extrusion apparatus 301 comprises ahead die 305, a body 309, and a hopper 307. The hopper 307 is forreceiving a thermoplastic material. The head die 305 has an inlet end352 and an outlet end 351. The body 309 has a body outlet end 321; thebody outlet end 321 and the inlet end 352 of the head die 305 areconnected by a pipe 330 for conveying a material to the head die 305.The body 309 also has a feed inlet 323 connected to the hopper 307 forreceiving a material from the hopper 307. The body 309 is provided witha drive mechanism, for example, a drive screw (not shown). The head die305 has a suitable width and thickness for accommodating a materialtransferred from the body 309, and the die cavity of the head die 305 issubstantially flat, so that a material transferred from the body can bemolded into a flat shape. The molding apparatus 302 has a plurality ofrollers 328 for cooling and molding.

The cast heat press molding process shown in FIGS. 3A and 3B is asfollows:

As shown in FIG. 3A, particles of a first thermoplastic material areadded to the hopper 307. The particles of the first thermoplasticmaterial enter the body 309 through the feed inlet of the body 309. Theparticles of the first thermoplastic material are melted in the body 309to form a molten state and are mixed uniformly and then, by the drivemechanism of the body, are fed via the pipe 330 to the head die 305through the inlet end 352 of the head die 305. In the head die 305, thefirst thermoplastic material in a molten state is molded to form a firstplate thermoplastic material 360. The first plate thermoplastic material360 is output from the outlet end 351 of the head die 305 to the moldingroll 328 of the molding apparatus 302.

When the first plate thermoplastic material 360 is fed to the moldingroll 328, the metal mesh 102 is unwound from the metal mesh roll 12 sothat the unwound metal mesh 102 and the first plate thermoplasticmaterial 360 are in an up-down positional relationship while beingconveyed to the molding roll 328 of the molding apparatus 302,successively passing between the molding rolls 328.1 and 328.2 andbetween the molding rolls 328.2 and 328.3. The molding rolls 388.1,328.2 and 328.3 apply tensile and compressive forces to the first platethermoplastic material 360 and the metal mesh 102, so that the metalmesh 102 is embedded or at least partially embedded in the surface ofthe first plate thermoplastic material 360 to form a press-fitted plate310. Then, the press-fitted plate 310 is rolled into a press-fittedplate roll. As needed, the metal mesh 102 and the first platethermoplastic material 360 may pass through a plurality of rollers, ormay pass only two rollers.

Next, as shown in FIG. 3B, after the first step, the second step of thecast heat press molding process is shown in FIG. 3B. Similar to thefirst step, particles of a second thermoplastic material are added intothe body 309 from the hopper 307. The particles of the secondthermoplastic material may be the same as or different from theparticles of the first thermoplastic material. The particles of thesecond thermoplastic material enter the body 309 through the feed inletof the body 309. The particles of the second thermoplastic material aremelted in the body 309 to form a molten state and are mixed uniformlyand then, by the drive mechanism of the body, are fed via the pipe 330to the head die 305 through the inlet end 352 of the head die 305. Inthe head die 305, the second thermoplastic material in a molten state ismolded to form a second plate thermoplastic material 380 in a moltenstate. The second plate thermoplastic material 380 is output from theoutlet end 351 of the head die 305 to the molding roll 328 of themolding apparatus 302.

While the second plate thermoplastic material 380 is output from theoutlet end 351 of the head die 305 to the molding roll 328 of themolding apparatus 302, the press-fitted plate 310 formed as shown inFIG. 3A is unwound from the press-fitted plate roll. Thus, the unwoundpress-fitted plate 310 and the second plate thermoplastic material 380are simultaneously conveyed to the molding roll 328 of the moldingapparatus 302, successively passing between the molding rolls 328.1 and328.2 and between the molding rolls 328.2 and 328.3. In the process, oneside of the metal mesh 102 of the press-fitted plate 310 faces thesecond plate thermoplastic material 380. The molding roll 328 appliestensile and compressive forces to the second plate thermoplasticmaterial 380 and the press-fitted plate 310 such that the metal mesh 102of the press-fitted plate 310 is embedded or at least partially embeddedin the second plate thermoplastic material 380. In addition, the secondplate thermoplastic material 380 is in a molten state when it exits theoutlet end 351 of the head die. Therefore, when the molding roll 328presses the second plate thermoplastic material 380 and the press-fittedplate 310, the second plate thermoplastic material 380 in a molten statemay flow through the openings in the metal mesh 102 to come into contactwith the first plate thermoplastic material 360 of the press-fittedplate 310 and solidify after being cooled by the molding roll 328. As aresult, the second plate thermoplastic material 380 and the first platethermoplastic material 360, as if integrally molded, can remain firmlyand tightly bonded together over a long period of time. In addition,before the unwinding of the press-fitted plate roll to convey thepress-fitted plate 310 or the conveyance of the press-fitted plate 310to the molding roll 328, as needed, the press-fitted plate 310 may beselectively heated so that the first plate thermoplastic material 360therein reaches a molten state, thereby achieving a firmer and tighterbonding between the first plate thermoplastic material 360 and thesecond plate thermoplastic material 380.

By the above-mentioned cast heat press molding process shown in FIGS. 3Aand 3B, the insulating composite plate 100 of the present application isobtained.

In the above-mentioned cast heat press molding process, desiredthicknesses of the upper plate layer 101 and the lower plate layer 103can be obtained by controlling the speed at which the first platethermoplastic material and the second plate thermoplastic material exitthe head die 305 and the rotational speed of the molding roll 328.

FIG. 4 shows a co-extrusion process for producing an insulatingcomposite plate according to the present application, the processcomprising two extrusion apparatuses and one molding apparatus. As shownin FIG. 4, a first extrusion apparatus 301.1 produces the first platethermoplastic material 360, and a second extrusion apparatus 301.2produces the second plate thermoplastic material 380; the first platethermoplastic material 360, the metal mesh 102, and the second platethermoplastic material 380 are molded together by the molding apparatus302 to produce the plate 100.

Particles of the first thermoplastic material are added into the body309.1 through the hopper 307.1. The first thermoplastic material meltsin the body 309.1 to form a molten state and, by the drive mechanism ofthe body 309.1, is fed via the pipe 330.1 to the head die 305.1 throughthe inlet end 352.1 of the head die 305.1. In the head die 305.1, thefirst thermoplastic material in a molten state is molded to form a firstplate thermoplastic material 360 in a molten state. The second platethermoplastic material 360 is output from the outlet end 351.1 of thehead die 305.1 to the molding roll 328 of the molding apparatus 302.

At the same time, particles of the second thermoplastic material areadded into the body 309.2 through the hopper 307.2. The particles of thesecond thermoplastic material can be the same as or different from theparticles of the first thermoplastic material. The second thermoplasticmaterial melts in the body 309.2 to form a molten state and, by thedrive mechanism of the body 309.2, is fed via the pipe 330.2 to the headdie 305.2 through the inlet end 352.2 of the head die 305.2. In the headdie 305.2, the second thermoplastic material in a molten state is moldedto form a second plate thermoplastic material 380 in a molten state. Thesecond plate thermoplastic material 380 is output from the outlet end351.2 of the head die 305.2 to the molding roll 328 of the moldingapparatus 302.

At the same time, the metal mesh 102 is unwound from the metal mesh roll12 so that the unwound metal mesh 102, the first plate thermoplasticmaterial 360, and the second plate thermoplastic material 380 aresimultaneously conveyed to the molding roll 328 of the molding apparatus302, successively passing between the molding rolls 328.1 and 328.2 andbetween the molding rolls 328.2 and 328.3. In this process, the metalmesh 102 is located between the first plate thermoplastic material 360and the second plate thermoplastic material 380. The molding rolls328.1, 328.2, and 328.3 apply tensile and compressive forces to thefirst plate thermoplastic material 360, the second plate thermoplasticmaterial 380, and the metal mesh 102 such that the metal mesh 102 isembedded or at least partially embedded in the surfaces of the firstplate thermoplastic material 360 and the second plate thermoplasticmaterial 380. In addition, the first plate thermoplastic material 360and the second plate thermoplastic material 380 are in a molten statewhen exiting the outlet ends 351.1 and 351.2 of the head die. Therefore,when the molding roll 328 presses the first plate thermoplastic material360, the second plate thermoplastic material 380, and the press-fittedplate 310, the first plate thermoplastic material 360 and the secondplate thermoplastic material 380 in a molten state may flow through theopenings in the metal mesh 102 to come into contact with each other andsolidify after being cooled by the molding roll 328. As a result, thesecond plate thermoplastic material 380 and the first platethermoplastic material 360, as if integrally molded, can remain firmlyand tightly bonded together over a long period of time.

As needed, the metal mesh 102, the first plate thermoplastic material360, and the second plate thermoplastic material 380 may pass through aplurality of rollers, or may pass through only two rollers.

In the composite plate 100 made by the above-mentioned two processes,the upper plate layer 101 and the lower plate layer 103 are bondedtogether without using an additional medium (e.g., glue), as if formedintegrally. Therefore, the middle plate layer 102, the upper plate layer101, and the lower plate layer 103 of the metal mesh can be firmly andtightly bonded together for a long time, not prone to separation. Inaddition, there is no gap between the middle plate layer 102, the upperplate layer 101, and the lower plate layer 103. Thus, moisture cannotenter between the middle plate layer 102, the upper plate layer 101, andthe lower plate layer 103 to corrode the metal mesh.

The following are embodiments of composite plate samples produced bycast heat press molding. The materials used in these embodiments were asfollows: PP, manufactured by ITW Electronic Components/Products(Shanghai) Co., Ltd. under the trade name Formex GK; the copper mesh wasan 80-opening commercial copper mesh, wherein the diameter of the copperwire was 0.1 mm, the spacing of adjacent copper wires was 0.2 mm, thethickness was 0.15 mm, and the copper content was 99.8%.

Embodiment 1

Using the method of cast heat press molding, PP particles wereplasticized and molded to obtain an upper plate layer. The thickness ofthe upper plate layer obtained by molding was 0.13 mm. The upper platelayer obtained by molding and the copper mesh placed between the headdie and the roller were cooled and molded at the same time by the rollerto obtain a press-fitted plate. The PP particles were then plasticizedand molded to obtain a lower plate layer, which was kept 0.76 mm thick.The press-fitted plate of the previously molded upper plate layer andthe copper mesh was placed between the head die and the roller, and wasrolled, cooled, and molded together with the lower plate layer to obtainan insulating composite plate.

Embodiment 2

Using the method of cast heat press molding, PP particles wereplasticized and molded to obtain an upper plate layer. The thickness ofthe upper plate layer obtained by molding was 0.25 mm. The upper platelayer obtained by molding and the copper mesh placed between the headdie and the roller were cooled and molded at the same time by the rollerto obtain a press-fitted plate. The PP particles were then plasticizedand molded to obtain a lower plate layer, which was kept 2.5 mm thick.The press-fitted plate of the previously molded upper plate layer andthe copper mesh was placed between the head die and the roller, and wasrolled, cooled, and molded together with the lower plate layer to obtainan insulating composite plate.

Embodiment 3

Using the method of cast heat press molding, PP particles wereplasticized and molded to obtain an upper plate layer. The thickness ofthe upper plate layer obtained by molding was 0.43 mm. The upper platelayer obtained by molding and the copper mesh placed between the headdie and the roller were cooled and molded at the same time by the rollerto obtain a press-fitted plate. The PP particles were then plasticizedand molded to obtain a lower plate layer, which was kept 2.5 mm thick.The press-fitted plate of the previously molded upper plate layer andthe copper mesh was placed between the head die and the roller, and wasrolled, cooled, and molded together with the lower plate layer to obtainan insulating composite plate.

Embodiment 4

Using the method of cast heat press molding, PP particles wereplasticized and molded to obtain an upper plate layer. The thickness ofthe upper plate layer obtained by molding was 0.13 mm. The upper platelayer obtained by molding and the copper mesh placed between the headdie and the roller were cooled and molded at the same time by the rollerto obtain a press-fitted plate. The PP particles were then plasticizedand molded to obtain a lower plate layer, which was kept 0.76 mm thick.The press-fitted plate of the previously molded upper plate layer andthe copper mesh was placed between the head die and the roller, and wasrolled, cooled, and molded together with the lower plate layer to obtainan insulating composite plate.

The four samples produced were compared to observe their surfaceeffects. In addition, the four samples and aluminum foils wererespectively used to wrap self-made battery packs; the battery packswere energized and different frequencies were configured. The electricfield intensities outside the battery packs before and after the foursamples produced and the aluminum foils were used to wrap the batterypacks were tested to obtain the differences in electric field intensityoutside the battery packs before and after the four samples produced andthe aluminum foils were used to wrap the battery packs. Thesedifferences reflected the electromagnetic shielding effects of the foursamples produced and the aluminum foils. The following table lists theresults of the experiment on the differences in electric field intensityoutside the battery packs before and after the four samples produced andthe aluminum foils were respectively used to wrap the battery packs at50 MHz:

Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Aluminum foilThickness of 0.13 0.25 0.43 0.13 Total the upper plate thickness 0.15layer/mm Thickness of 0.15 0.15 0.15 0.15 the middle plate layer/mmThickness of 2.50 2.50 2.50 0.76 the lower plate layer/mm Difference in28.26 28.33 28.45 28.12 28.21 electric field intensity dBuV/m Platesurface There were There were Very smooth There were effect obviousfolds. slight folds. obvious folds.

The experimental results showed that the four insulating compositeplates produced by compounding PP and a copper mesh according to thepresent invention effectively decreased the electric field intensitiesoutside the wrapped battery packs (see the measured differences inelectric field intensity outside the battery packs before and after thebattery packs were wrapped); in addition, the electromagnetic shieldingeffect of the four insulating composite plates produced was similar tothat of the aluminum foils (having the same thickness as theintermediate copper mesh of the four insulating composite platesproduced). Therefore, an insulating composite plate of the presentinvention has a good electromagnetic shielding effect. In addition, whenthe thickness of the upper plate layer of an insulating composite plateof the present invention is greater than 0.43 mm, since in this case theupper plate layer has a large thickness and a high strength, the upperplate layer is not easily deformed when being pressed together with thecopper mesh and the lower plate layer. Therefore, an insulatingcomposite plate produced has a good surface effect, smooth andaesthetically pleasing.

While some features of the present invention have been particularlyillustrated and described above with reference to specific embodiments,it should be understood that various improvements and alterations may bemade by those of ordinary skill in the present art without departingfrom the spirit and scope of the present invention as defined by theClaims attached.

1. An insulating composite plate, comprising: an upper plate layer and alower plate layer, the upper plate layer and the lower plate layer beingmade of a thermoplastic material; and a middle plate layer locatedbetween the upper plate layer and the lower plate layer, the middleplate layer being a metal mesh; the upper surface of the middle platelayer and the lower surface of the upper plate layer are bondedtogether, and the lower surface of the middle plate layer and the uppersurface of the lower plate layer are bonded together.
 2. The insulatingcomposite plate as claimed in claim 1, wherein the upper plate layer andthe lower plate layer are bonded together at the position of theopenings of the metal mesh.
 3. The insulating composite plate as claimedin claim 2, wherein: the insulating composite plate is shaped to havefour walls extending from its peripheral edges to form a battery packcover; the battery pack cover is configured to fit onto a battery packhousing.
 4. The insulating composite plate as claimed in claim 1,wherein: the insulating composite plate is made by cast heat pressmolding or co-extrusion process; in the manufacturing process, at leastone of the thermoplastic material on the upper plate layer or the lowerplate layer penetrates the openings of the metal mesh in a molten state,and comes into contact with the lower plate layer or the upper platelayer on the other side of the metal mesh; and after the thermoplasticmaterial in a molten state is solidified, the upper plate layer isintegrated with the lower plate layer so that the metal mesh is lockedbetween the upper plate layer and the lower plate layer.
 5. Theinsulating composite plate as claimed in claim 1, wherein the plateupper layer and the plate lower layer are bonded together without theuse of any additional medium.
 6. The insulating composite plate asclaimed in claim 1, wherein the upper plate layer and the lower platelayer are made of the same or different materials.
 7. The insulatingcomposite plate as claimed in claim 1, wherein the thermoplasticmaterial is a thermoplastic resin; the thermoplastic material may beselected from PP, PC or PET.
 8. The insulating composite plate asclaimed in claim 1, wherein the upper plate layer and the lower platelayer do not contain or contain a flame retardant.
 9. The insulatingcomposite plate as claimed in claim 8, wherein the flame retardant is ahalogen-containing flame retardant or a halogen-free flame retardant,the halogen-containing flame retardant being a bromine-containing flameretardant or a chlorine-containing flame retardant, the halogen-freeflame retardant being a phosphorus-containing flame retardant or anitrogen-containing or silicon-containing or sulfur-containing orinorganic flame retardant.
 10. The insulating composite plate as claimedin claim 1, wherein the metal mesh is made of copper, or another metal,or an alloy of copper or another metal.
 11. The insulating compositeplate as claimed in claim 1, wherein the metal mesh has a specificationof 20 openings to 400 openings.
 12. The insulating composite plate asclaimed in claim 1, wherein the thickness of the upper plate layer is0.05 mm to 4.0 mm; the thickness of the middle plate layer is 0.05 mm to0.4 mm; the thickness of the lower plate layer is 0.05 mm to 4.0 mm, andthe thickness of the plate is 0.15 mm to 5.0 mm.
 13. A method forproducing an insulating composite plate, the method comprising: (a)extruding particles of a first thermoplastic material on an extruder tomelt it to form a first thermoplastic material in a molten state; (b)the first thermoplastic material in a molten state flows out of theextruder and enters a head die through a connecting pipe and is formedinto a first plate thermoplastic material in the head die; (c) providinga metal mesh; (d) simultaneously conveying the metal mesh and the firstplate thermoplastic material to a cooling molding roll so that the firstplate thermoplastic material is press-fitted on one surface of the metalmesh to form a press-fitted sheet composed of the first platethermoplastic material and the metal mesh; (f) extruding particles of asecond thermoplastic material on the extruder to melt it to form asecond thermoplastic material in a molten state; (g) the secondthermoplastic material in a molten state flows out of the extruder andenters the head die through the connecting pipe and is formed into asecond plate thermoplastic material in the head die; and (h)simultaneously conveying the press-fitted sheet and the second platethermoplastic material to the cooling molding roll so that the secondplate thermoplastic material is press-fitted on the other surface of themetal mesh, forming the insulating composite plate comprising a middleplate layer composed of the metal mesh and an upper plate layer and alower plate layer respectively composed of the first plate thermoplasticmaterial and the second plate thermoplastic material.
 14. The method forproducing an insulating composite plate as claimed in claim 13,comprising step (i) of heating the press-fitted sheet before step (h).15. A method for producing an insulating composite plate, the methodcomprising: (a) extruding particles of a first thermoplastic material ona first extruder to melt it to form a first thermoplastic material in amolten state; (b) the first thermoplastic material in a molten stateflows out of the first extruder and enters a first head die through afirst connecting pipe and is formed into a first plate thermoplasticmaterial in the first head die; (c) extruding particles of a secondthermoplastic material on a second extruder to melt it to form a secondthermoplastic material in a molten state; (d) the second thermoplasticmaterial in a molten state flows out of the second extruder and enters asecond head die through a second connecting pipe and is formed into asecond plate thermoplastic material in the second head die; (e)providing a metal mesh; and (f) simultaneously conveying the metal mesh,the first plate thermoplastic material, and the second platethermoplastic material to a cooling molding roll so that the first platethermoplastic material and the second plate thermoplastic material arerespectively press-fitted on the two opposing surfaces of the metalmesh, forming the insulating composite plate comprising a middle platelayer composed of the metal mesh and an upper plate layer and a lowerplate layer respectively composed of the first plate thermoplasticmaterial and the second plate thermoplastic material.
 16. The insulatingcomposite plate as claimed in claim 1, wherein the metal mesh has aspecification of 50 openings to 100 openings.
 17. The insulatingcomposite plate as claimed in claim 1, wherein the thickness of theupper plate layer is 0.43 mm to 2 mm; the thickness of the middle platelayer is 0.05 mm to 0.4 mm; the thickness of the lower plate layer ispreferably 0.43 mm to 2 mm, and the thickness of the plate is 1.5 mm to3 mm.
 18. The insulating composite plate as claimed in claim 1, whereinthe thickness of the upper plate layer is 0.43 mm to 2 mm; the thicknessof the middle plate layer is 0.05 mm to 0.4 mm; the thickness of thelower plate layer is preferably 0.43 mm to 2 mm, and the thickness ofthe plate is less than 4 mm.